57 lines
2.1 KiB
Markdown
57 lines
2.1 KiB
Markdown
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# Fuzzer for libmedia_codecserviceregistrant
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## Plugin Design Considerations
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The fuzzer plugin for libmedia_codecserviceregistrant is designed based on the understanding of the library and tries to achieve the following:
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##### Maximize code coverage
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The configuration parameters are not hardcoded, but instead selected based on
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incoming data. This ensures more code paths are reached by the fuzzer.
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libmedia_codecserviceregistrant supports the following parameters:
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1. C2String (parameter name: `c2String`)
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2. Width (parameter name: `width`)
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3. Height (parameter name: `height`)
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4. SamplingRate (parameter name: `samplingRate`)
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5. Channels (parameter name: `channels`)
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6. Stream (parameter name: `stream`)
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| Parameter| Valid Values| Configured Value|
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|------------- |-------------| ----- |
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| `c2String` |`String` | Value obtained from FuzzedDataProvider|
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| `width` |`UINT32_MIN` to `UINT32_MAX` | Value obtained from FuzzedDataProvider|
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| `height` |`UINT32_MIN` to `UINT32_MAX` | Value obtained from FuzzedDataProvider|
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| `samplingRate` |`UINT32_MIN` to `UINT32_MAX` | Value obtained from FuzzedDataProvider|
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| `channels` |`UINT32_MIN` to `UINT32_MAX` | Value obtained from FuzzedDataProvider|
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| `stream` |`UINT32_MIN` to `UINT32_MAX` | Value obtained from FuzzedDataProvider|
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This also ensures that the plugin is always deterministic for any given input.
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##### Maximize utilization of input data
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The plugin feeds the entire input data to the libmedia_codecserviceregistrant module.
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This ensures that the plugin tolerates any kind of input (empty, huge,
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malformed, etc) and doesnt `exit()` on any input and thereby increasing the
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chance of identifying vulnerabilities.
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## Build
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This describes steps to build codecServiceRegistrant_fuzzer binary.
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### Android
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#### Steps to build
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Build the fuzzer
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```
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$ mm -j$(nproc) codecServiceRegistrant_fuzzer
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```
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#### Steps to run
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To run on device
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```
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$ adb sync data
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$ adb shell /data/fuzz/${TARGET_ARCH}/codecServiceRegistrant_fuzzer/codecServiceRegistrant_fuzzer
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```
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## References:
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* http://llvm.org/docs/LibFuzzer.html
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* https://github.com/google/oss-fuzz
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